Cardiac magnetic resonance imaging (MRI) shows great potential but requires substantial improvements in contrast, spatial resolution, and speed. Two recent advances of particular interest are the development of balanced steady state free precession (SSFP) imaging sequences (equivalently known as True-FISP, FIESTA, or Balanced-FFE), and the development and availability of 3 Telsa clinical scanners. Both provide substantial improvements in SNR and contrast but together, 3T and SSFP are relatively incompatible for rapid high-resolution cardiac imaging. Conventional SSFP is critically limited by banding artifacts that require the use of repetition times of 3 ms or less in the heart at 3T. This limits the achievable spatial resolution, and prevents the use of time-efficient acquisition schemes to reduce scan time. The aim of this proposal is to develop and validate a new imaging technique, which we call Wideband SSFP, that uses alternating repetition times to achieve a steady-state that provides up to double the bandwidth of conventional SSFP, with comparable SNR and contrast. This bandwidth improvement allows the use of longer imaging TRs which will supporting readouts on the order of 4 ms, to enable high spatial resolution (increased readout gradient area) and high temporal resolution (using time-efficient acquisition schemes). The goal of this proposal is to fully characterize and develop Wideband SSFP and apply it to rapid high- resolution cardiac MRI at 3 Tesla. Utilizing SNR improvements from the 3T platform and from SSFP sequences to achieve higher spatial and temporal resolution directly addresses the current limitations of clinical cardiac MRI. [unreadable] [unreadable]